Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F26—DRYING
  • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
  • F26B3/00—Drying solid materials or objects by processes involving the application of heat
  • F26B3/02—Drying solid materials or objects by processes involving the application of heat by convection, i.e. heat being conveyed from a heat source to the materials or objects to be dried by a gas or vapour, e.g. air
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23K—FODDER
  • A23K10/00—Animal feeding-stuffs
  • A23K10/30—Animal feeding-stuffs from material of plant origin, e.g. roots, seeds or hay; from material of fungal origin, e.g. mushrooms
  • A23K10/37—Animal feeding-stuffs from material of plant origin, e.g. roots, seeds or hay; from material of fungal origin, e.g. mushrooms from waste material
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23K—FODDER
  • A23K40/00—Shaping or working-up of animal feeding-stuffs
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
  • A23L11/00—Pulses, i.e. fruits of leguminous plants, for production of food; Products from legumes; Preparation or treatment thereof
  • A23L11/30—Removing undesirable substances, e.g. bitter substances
  • A23L11/31—Removing undesirable substances, e.g. bitter substances by heating without chemical treatment, e.g. steam treatment, cooking
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
  • A23L5/00—Preparation or treatment of foods or foodstuffs, in general; Food or foodstuffs obtained thereby; Materials therefor
  • A23L5/20—Removal of unwanted matter, e.g. deodorisation or detoxification
  • A23L5/21—Removal of unwanted matter, e.g. deodorisation or detoxification by heating without chemical treatment, e.g. steam treatment, cooking
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F26—DRYING
  • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
  • F26B17/00—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement
  • F26B17/001—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement the material moving down superimposed floors
  • F26B17/005—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement the material moving down superimposed floors with rotating floors, e.g. around a vertical axis, which may have scrapers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F26—DRYING
  • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
  • F26B25/00—Details of general application not covered by group F26B21/00 or F26B23/00
  • F26B25/005—Treatment of dryer exhaust gases
  • F26B25/006—Separating volatiles, e.g. recovering solvents from dryer exhaust gases
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
  • Y02A40/00—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production
  • Y02A40/90—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production in food processing or handling, e.g. food conservation
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P60/00—Technologies relating to agriculture, livestock or agroalimentary industries
  • Y02P60/80—Food processing, e.g. use of renewable energies or variable speed drives in handling, conveying or stacking
  • Y02P60/87—Re-use of by-products of food processing for fodder production

Definitions

• the invention relates to an improved apparatus and process for simultaneously evaporating residual solvent from spent oilseed material while subjecting such spent oilseed material to conditions that create oilseed meal with improved protein digestibility, while maintaining low residual solvent and adequate inactivation of anti-nutritional factors.
• the resultant liquid fraction is known in the trade as "miscella", a solution of vegetable oil in the organic solvent, and the resultant solid fraction is known in the trade as "spent material", the extraction residue soaked with organic solvent.
• the crude vegetable oil is further processed to produce edible oil products.
• an oilseed meal is produced that is primarily used as a high protein animal feed ingredient.
• the spent material from the solvent extraction process is generally soaked with twenty-five to thirty-five percent (25-35%) solvent by weight.
• the downstream process of evaporating the solvent from said spent material is known in the trade as "desolventizing", whose primary purpose is to remove the organic solvent to as low a residual solvent content as possible for both feed safety and environmental purposes.
• oilseeds contain anti-nutritional factors (ANF) that prevent key amino acids in oilseed meals from being digested by mono-gastric animals such as poultry and swine.
• ANF anti-nutritional factors
• Said ANF generally consist of heat labile peptides such as the trypsin inhibitors present in soybeans. Accordingly, heating the oilseed meal to a sufficiently high temperature with adequate moisture present for a sufficiently long period inactivates these ANF by denaturing said peptides.
• the term used in the trade for this process is "toasting".
• the spent material continuously enters the DT vessel and drops onto a tray inside, known in the trade as a "pre-desolventizing" (PD) tray, which is an indirect steam-heated horizontal disc with a surface temperature typically 135-155°C.
• PD pre-desolventizing
• a shallow layer of spent material is stirred above the surface of the PD tray by stirring blades extending from a rotating centrally located shaft.
• the temperature of the spent material is increased to the boiling range of the solvent, typically 60-70 0 C, where the organic solvent begins to evaporate.
• a typical DT has two to four PD trays stacked vertically in series, where approximately ten to twenty percent (10-20%) of the initial solvent is evaporated, while the temperature remains 50-60 0 C and the moisture remains relatively constant at ten to twelve percent (10-12%).
• CC tray which is an indirect steam-heated horizontal disc with a surface temperature typically 135-155 0 C that has special apertures therein that allow ascending superheated water vapor to rise through.
• a deep layer of spent material is stirred above the surface of the CC tray by stirring blades extending from a rotating centrally located shaft.
• this first CC tray When the spent material exits this first CC tray it will typically contain less than one percent residual solvent by weight with a moisture content of eighteen to twenty-two percent (18-22%) by weight and a temperature of 95-100 0 C. These moisture and temperature conditions allow for destruction of ANF and reduction of protein digestibility in the spent material.
• a typical DT has two to four CC trays stacked vertically in series. After the first CC tray, the temperature and moisture remain relatively constant. The primary purpose of the remaining CC trays is to allow time for further stripping of the remaining traces of residual solvent by rising superheated water vapor and time for adequate destruction of the ANF. Reduction of the protein digestibility of the spent material continues on the remaining CC trays.
• the spent material After the spent material exits the final CC tray, the spent material continuously enters the next chamber of the DT vessel.
• the spent material drops onto a tray inside, known in the trade as a "sparge” (SP) tray, which is a hollow horizontal disc with perforated upper surface for even distribution of superheated water vapor into the DT.
• SP separatge
• a deep layer of spent material is stirred above the surface of the SP tray by stirring blades extending from a rotating centrally located shaft.
• the evenly distributed superheated water vapor rises through the spent material to achieve efficient removal of the remaining residual solvent to acceptable levels.
• Final destruction of ANF and reduction of protein digestibility also occur on the SP tray.
• the desolventized, toasted meal When the desolventized, toasted meal exits the DT vessel it will typically contain less than 0.05% solvent by weight with a moisture content of eighteen to twenty-two percent (18-22%) by weight and a temperature of 105 to 110 0 C.
• the ANF of the desolventized, toasted meal as measured by urease delta pH is typically less than 0.15 and the protein digestibility as measured by PDI is typically 20-30%.
• the solvent evaporated from the spent material along with an equilibrium quantity of water vapor typically exits the upper roof of the DT vessel.
• This vapor stream is generally 67-75 0 C temperature and is composed of 90-95% solvent vapor in equilibrium with 5-10% of water vapor.
• This vapor stream often contains traces of meal dust and therefore passes through a vapor scrubbing apparatus before passing on to heat recovery.
• superheated hexane vapors are used to evaporate solvent from the spent material at the beginning of the DT apparatus and process.
• This method allows a substantial reduction in solvent content in the spent material without increasing the spent material moisture or temperature. The result is less solvent proceeding to the uppermost CC tray which in turn requires less condensation of superheated water vapors into the spent material, which in turn allows the moisture to be controlled in the spent material in the ideal range of 15-17% by weight. Under the conditions of 15-17% moisture by weight, 105-110 0 C temperature and 20-30 minutes residence time, ANF is still adequately deactivated while protein digestibility is substantially improved.
• the recycled water vapor in combination with the reduced rate of rising water vapor introduced at the SP tray enables the flux rate through the spent material to be increased over the minimum acceptable flux rate of 300 kg/hr/m 2 .
• the flux rate through the spent material can be increased over the minimum acceptable flux rate of 300 kg/hr/m 2 .
• meal can be produced with less than 500 parts per million (ppm), and ideally less than 250 ppm solvent by weight.
• the ideal conditions of 15-17% moisture by weight, 105- 110 0 C temperature, 20-30 minutes residence time, and a superheated water vapor flux rate of greater than 300 kg/hr/m 2 can all be simultaneously achieved.
• one aspect of the invention pertains to superheated solvent recycle at the initial stage of the DT apparatus and process.
• Another aspect of the invention involves superheated water vapor recycle at the final stage of the DT apparatus and process.
• Fig. 1 is a graph illustrating data gathered from a benchtop scale DT showing the impact of PDI in meal at varying levels of moisture;
• Fig. 2 is a graph illustrating data gathered from a benchtop scale DT showing the impact of ANF in meal at varying levels of moisture;
• Fig. 3 is a cross-section drawing of one embodiment of the improved
• the apparatus comprises a vertical cylindrical housing (1) with an inlet for the spent material at the top of said housing (2) and an outlet for the desolventized, toasted meal at the bottom of said housing (3).
• the spent material is stirred above internal trays (4,5,6,7) by agitators (8) connected to a rotating vertical shaft (9).
• the trays are serially arranged from an upstream location to a downstream location within the interior of the housing.
• the spent material passes from an upstream direction to a downstream direction from tray to tray by means of a variable speed rotary valve (10), which also controls the spent material layer depth on each tray.
• the first, top, upstream tray (4) is an enclosed steam-heated tray with apertures therein which allow superheated solvent vapors from the tray below to rise through the spent material layer supported above. Solvent is primarily evaporated from the spent material on this tray by the rising solvent vapor losing its superheat, and secondarily by transfer of heat from the steam-heated tray surface.
• the second tray (5) is an enclosed steam-heated tray with no apertures. Solvent is evaporated from the spent material on this tray by transfer of heat from the steam-heated tray surface. This tray (5) forms a vapor seal from the tray below.
• These two trays (4,5) act as a pair for injection of superheated solvent vapor into the spent material. This apparatus can have as little as one and as many as four pairs of these trays (4,5) as required to supply sufficient superheated solvent to evaporate adequate solvent from the spent material prior to the spent material passing to the next zone of the DT apparatus.
• the fifth, sixth and seventh trays (6) are enclosed steam-heated trays with apertures which allow superheated water vapors from the tray below to rise through the spent material layer supported above. Solvent is primarily evaporated from the spent material on these trays by the rising water vapor condensing into the spent material, and secondarily by transfer of heat from the steam-heated tray surface.
• the final or most downstream tray shown (T) is an enclosed chamber with a plurality of small apertures which allow superheated water vapor in the form of low pressure steam to enter the apparatus and pass through the spent material layer supported above.
• Solvent vapor with a slight amount of water vapor exits the sidewall of the apparatus as shown at exits (12) and passes to a vapor scrubbing device (13) to remove meal dust before this vapor passes on to heat recovery within the overall solvent extraction process (14).
• the apparatus is equipped with a superheated solvent vapor recycle system.
• a portion of the solvent vapor with slight water vapor exiting the vapor scrubbing device (13) is pulled into a spark-proof blower (15).
• the spark-proof blower increases the pressure and pushes the vapors through the tubes of a shell and tube heat exchanger (16). Steam on the shell side of this heat exchanger is used to superheat the mostly solvent vapors passing through.
• the mostly superheated solvent vapors enter the sidewall of the vessel, between the pairs of trays (4,5) as shown at 17. These superheated vapors then rise through the apertures in the tray above, providing heat to evaporate solvent at low temperature.
• the cool, evaporated vapors exit the sidewall of the vessel (12) and pass to the vapor scrubbing device (13), completing the recycle loop.
• the apparatus is equipped with a superheated water vapor recycle system.
• a portion of the superheated water vapor with slight solvent vapor is pulled from the sidewall of the vessel as shown at (18) under the upper countercurrent tray (6) by a spark-proof blower or steam ejector apparatus (19) which in turn passes the vapor through a steam-heated shell and tube heat exchanger (20) to optionally add superheat and then returns this vapor back through the sidewall of the vessel into the headspace above the meal of the lowest tray (7) as shown at (21).
• This return of vapor increases the flux rate of superheated water vapor through the layers of spent material supported on the trays (6) to improve stripping of solvent from the spent material.
• Water vapors (22) from the solvent extraction process may also be introduced into the superheated water vapor loop for heat recovery purposes by pushing such vapors with a steam ejector (23).
• the invention is directed toward an apparatus for processing spent material from a solvent extraction process wherein spent material enters the top of a vertical cylindrical vessel (1) with trays (4,5,6,7) disposed horizontally therein wherein spent material is conveyed around such trays by stirrers (8) that are connected to a vertical rotating champ (9) at the center of the vessel and such spent material is conveyed from tray to tray by rotary airlocks (10).
• the spent material is subjected to a combination of direct contact by superheated hexane, direct contact by superheated water vapor, and heat transferred from the trays (4,5,6) to enable the solvent to be evaporated and the spent material adequately toasted.
• a pair of steam heated trays (4,5) is provided in the apparatus wherein the bottom tray acts as a vapor seal and the top tray acts as a superheated solvent vapor sparging device to enable significant solvent to be evaporated from spent material with a minimum rise in temperature or moisture.
• a superheated solvent vapor recycle loop wherein primary solvent vapors, greater than 90% solvent vapor and less than 10% water vapor exit the apparatus and are returned from the vapor scrubber (13) to a vapor tight, spark proof blower (15) wherein such vapors are superheated in a steam-heated shell and tube heat exchanger (16) and then introduced through the sidewall of the vessel as shown at (17) between the pair of steam heated trays as defined above which serve as a combination vapor seal and superheated solvent vapor sparging device.
• the solvent vapors rise through the spent material layer supported on the upper tray (4) evaporating solvent and such solvent exits the sidewall at the upstream end of the vessel as shown at the upstream exit and proceeds to a vapor scrubber (13) to remove meal dust.
• the content of the residual solvent in the spent material after the superheated solvent vapor recycle loop through water vapor condensation in uppermost deep meal layer tray (6) increases the meal moisture to 15- 17% moisture, more ideally 15.5-16.5% moisture, and most preferably 16% moisture.
• the desolventized toasted spent material exiting the apparatus has an ANF as measured by urease delta pH of 0.05 to 0.20, and more ideally, 0.010 to 0.015.
• the dissolved, toasted spent material exiting the apparatus has a protein solubility as measured by PDI exceeding 30% and more ideally exceeding 35%, and most preferentially exceeding 40%.
• a superheated water vapor recycle loop is provided wherein primary water vapors, greater than 95% water vapor and less than 5% solvent vapor, are pulled through the sidewall of the vessel at the head space under the first tray as shown at (18) to a vapor type, spark proof blower or steam ejector 19 wherein such vapors are superheated in a steam heated shell and tube heat exchanger (20) and then reintroduced through the sidewall of the vessel in the head space over the last tray with deep layer material as shown at the arrow 21.
• Such vapors rise through the tray (6) and spent material supported above to strip out solvent.
• the recycled vapor flow is adjusted to obtain a flux rate through the spent material layer supported by the tray (6) of 300-700 kg/hr/m 2 , and more ideally 400- 600 kg/hr/m 2 , and most ideally 500 kg/hr/m 2 .
• the desolventized toasted spent material existing the apparatus (3) has a residual solvent content of less than 500 ppm, and more ideally less than 300 ppm, and most ideally less than 200 ppm.
• any water vapor source from the solvent extraction process can have its heat recovered by using a steam ejector 23 or the like to push the vapors into the superheated water vapor recycle loop.

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• Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Polymers & Plastics (AREA)
• Chemical & Material Sciences (AREA)
• Food Science & Technology (AREA)
• Health & Medical Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
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• Agronomy & Crop Science (AREA)
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• Processing Of Solid Wastes (AREA)
• Extraction Or Liquid Replacement (AREA)

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• 2010
  • 2010-05-06 EP EP10718753.6A patent/EP2437619B1/en active Active
  • 2010-05-06 BR BRPI1010779A patent/BRPI1010779B1/pt active IP Right Grant
  • 2010-05-06 US US13/322,947 patent/US8720082B2/en active Active
  • 2010-05-06 WO PCT/US2010/001346 patent/WO2010141053A1/en active Application Filing
• 2014
  • 2014-03-25 US US14/224,552 patent/US9250013B2/en active Active

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